Dragonlance already has at least three races that the dragonborn stomps all over in terms of an existing niche. Draconians, which have been playable throughout 3rd edition, are not dragonborn but share many characteristics. Dragonspawn, which we provided playable rules for in Dragons of Krynn, are much more like dragonborn in some ways and yet nothing like them in others. And the bakali, the Krynnish term for the lizardfolk races (including troglodytes, kobolds, etc) have the "ancient empire servants of dragons" thing going for them, but they're not actually descended from dragons or have draconic traits.
In addition, the personality that dragonborn have been given is a lot like that of the minotaurs of Krynn - martial, possessing a sense of honor, etc.
So, basically, I don't see dragonborn becoming a part of Dragonlance. I'm hoping the race gives enough of an inspiration in terms of rules handling that draconians, dragonspawn, and bakali might be well taken care of.
Cheers,
Cam